Claims:WE CLAIM:
1. A mechanism for indicating position of a vacuum circuit breaker, the vacuum circuit breaker is mounted on a cradle provided inside a vacuum circuit breaker compartment, the compartment having a horizontal slot provided on a front door thereof, the mechanism comprising:
a fixed member mounted on an inner surface of the front door, the fixed member having a slot corresponding to the horizontal slot of the front door, a pair of inwardly protruding members mounted on the fixed member along the slot defining a guiderail, the guiderail receives a moveable plate whereby the plate is moveable between a service position and a test position along the length of the guiderail; and
a moveable arm extending between a first end and a second end, the first end is pivotally mounted on the fixed member and the second end resting on a front surface of the vacuum circuit breaker, the moveable arm configured to pivotally move away from the fixed member during racking in of the vacuum circuit breaker and move towards the fixed member during racking out of the vacuum circuit breaker, wherein the moveable arm is coupled to the moveable plate whereby the moveable plate slides towards the service position during racking in of the vacuum circuit breaker and the moveable plate moves toward the test position during racking out of the vacuum circuit breaker.

2. The mechanism as claimed in 1, comprising a latching linkage adapted on the inner surface of the front door to actuate the mechanism, the latching linkage comprising a rod having laterally extending first and second arms at opposite ends thereof wherein the first arm is coupled with an adjustable lever arrangement pointing toward the cradle to accommodate variation in assemblies and the second arm rests against a resetting pin passing through the moveable arm.

3. The mechanism as claimed in 2, comprising a torsion spring disposed on the rod thereby pivotally mounting the rod on the fixed member.

4. The mechanism as claimed in claim 1, wherein a wheel is mounted adjacent the second end of the moveable arm and the wheel rests on the front surface of the vacuum circuit breaker.

5. The mechanism as claimed in claim 1, comprising an auto resetting arrangement, the auto resetting arrangement having at least one lateral spring connected to the resetting pin on one side and to a pivot pin passing through the moveable arm on another side.
, Description:FIELD OF THE INVENTION
[001] The invention relates to a mechanism for indicating position of a vacuum circuit breaker inside its enclosure.

BACKGROUND OF THE INVENTION
[002] Vacuum circuit breakers (VCB) are classified into withdrawable vacuum circuit breakers and fixed vacuum circuit breakers. In fixed VCBs, position of the main body of the VCB is fixed in a VCB compartment whereas in withdrawable VCBs, the main body of the VCB is mounted on a cradle which is provided inside the VCB compartment/panel.
[003] In withdrawable VCBs the main body of the VCB is periodically removed/ drawn out to facilitate maintenance and/or replacement of the associated switching devices. In order to facilitate removal, or otherwise to disconnect the VCB from an electrical circuit, the VCB is “racked out”, that is, disconnects in the VCB are moved from a connected position to a disconnected position.
[004] The withdrawable VCBs typically have two positions -1) service position; and 2) test position. In service position, the primary and secondary disconnects of the VCB are connected to a circuit whereas in test position, the primary disconnects are disconnected but the secondary disconnects are connected thereby allowing a user, for example, to check the functioning of secondary or control power. VCBs may be racked between these two positions. When racking out, the VCB is moved from the service position to the test position. In this regard, the VCBs can be racked in/out either remotely or manually by a user.
[005] Generally, indicators/stickers of the positions are provided on the VCB main body which is mounted on the cradle inside the VCB compartment/panel. A viewing window is provided on a front door of the VCB compartment. A user has to look inside the VCB compartment through the window to identify the position of the VCB.
[006] However, it is difficult/ dangerous for a user to look inside the VCB compartment to ascertain the position of the VCB while the VCB is being racked in/out or the VCB is service position. Further, the user is not able to identify any intermediate position since existing indication arrangement is actuated at the test and service positions only. Moreover, it is unsafe for operator to open the VCB compartment door when VCB in service position.
[007] Therefore, there exists a need for a mechanism for indicating position of a VCB which addresses at least the abovementioned problems.

SUMMARY OF THE INVENTION
[008] In an embodiment, the invention provides a mechanism for indicating position of a vacuum circuit breaker, the vacuum circuit breaker is mounted on a cradle provided inside a vacuum circuit breaker compartment, the compartment having a horizontal slot provided on a front door thereof, the mechanism comprising a fixed member mounted on an inner surface of the front door, the fixed member having a slot corresponding to the horizontal slot of the front door, a pair of inwardly protruding members mounted on the fixed member along the slot defining a guiderail, the guiderail receives a moveable plate whereby the plate is moveable between an service position/end and test position/end along the length of the guiderail, and a moveable arm extending between a first end and a second end, the first end is pivotally mounted on the fixed member and the second end resting on a front surface of the vacuum circuit breaker, the moveable arm configured to pivotally move away from the fixed member during raking in of the vacuum circuit breaker and move towards the fixed member during racking out of the vacuum circuit breaker, wherein the moveable arm is coupled to the moveable plate whereby the moveable plate slides towards the service position during racking in of the vacuum circuit breaker and the moveable plate moves toward the test position during racking out of the vacuum circuit breaker.
[009] In an embodiment of the present invention, the mechanism includes a latching linkage adapted on the inner surface of the front door to actuate the mechanism. The latching linkage comprising a rod having laterally extending first and second arms at opposite ends thereof wherein the first arm is coupled with an adjustable lever arrangement pointing toward the cradle to accommodate variation in assemblies and the second arm rests against a resetting pin passing through the moveable arm. In this regard, a torsion spring is disposed on the rod thereby pivotally mounting the rod on the fixed member.
[010] In another embodiment of the present invention, a wheel is mounted adjacent the second end of the moveable arm and the wheel rests on the front surface of the vacuum circuit breaker.
[011] Yet, in another embodiment of the present invention, the mechanism includes an auto resetting arrangement, the auto resetting arrangement having at least one lateral spring connected to the resetting pin on one side and to a pivot pin passing through the moveable arm on another side.

BRIEF DESCRIPTION OF THE DRAWINGS
[012] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 shows a mechanism for indicating position of a vacuum circuit breaker in accordance with an embodiment of the invention.
Figure 2 shows a mechanism which includes kinematics, latching linkage and auto resetting arrangement for indicating position of a vacuum circuit breaker in accordance with an embodiment of the invention.
Figure 3 shows a front door of vacuum circuit breaker showing position of the vacuum circuit breaker in accordance with an embodiment of the invention.
Figure 4 shows a cross sectional view of a vacuum circuit breaker compartment adapted with a mechanism for indicating position of a vacuum circuit breaker in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[013] The present invention is directed towards a mechanism for indicating position of a vacuum circuit breaker. In this regard, invention provides a mechanism which indicates the position of the vacuum circuit breaker on a slot provided on a front door of a vacuum circuit breaker compartment.
[014] Figures 1 and 2 shows a mechanism 100 for indicating a position of a vacuum circuit breaker. The mechanism comprising a fixed member 110 and a moveable arm 120. As shown, the fixed member has a slot 112, a pair of inwardly protruding members 114 defining a guiderail and a moveable plate 116.
[015] As shown, the moveable arm is extending between a first 122 end and a second end 124. In an embodiment, the first end of the moveable arm is pivotally mounted on the fixed member and the second end rests on a front surface of a vacuum circuit breaker mounted on the cradle inside the vacuum circuit breaker compartment 300. In this regard, the moveable arm can have pivotal movement about the pivot point- the second end.
[016] In an embodiment, a wheel 126 is mounted on the second end of the moveable arm. Accordingly, if the vacuum circuit breaker is racked in/out, the moveable arm moves pivotally about the first end and the wheel moves on the front surface of the vacuum circuit breaker.
[017] Figure 4 shows a cross sectional view of a vacuum circuit breaker compartment adapted with a mechanism for indicating position of a vacuum circuit breaker in accordance with an exemplary embodiment of the present invention. As shown, the moveable arm rests on the front surface of the vacuum circuit breaker 200.
[018] In an embodiment of the present invention, as shown in Figure 2, a torsion spring 128 is coupled to the first end of the moveable arm where the moveable arm is biased to pivotally move away from the fixed member because of the spring force.
[019] In a further embodiment of the present invention, a latching linkage is provided on the inner surface of the front door. The latching linkage includes a rod 130 having laterally extending between first and second arms 132, 134 provided at opposite ends of rod. In this regard, a torsion spring 144 is disposed on the rod thereby pivotally mounting the rod on the fixed member. The first arm is coupled with a lever arrangement with adjustment pointing toward the cradle to accommodate the variation in assemblies. The second arm rests against a resetting pin 141 passing through the moveable arm. The latching linkage is activated by means of pressing the first arm by cradle when front door is latched whereby mechanism is actuated as second arm de-latches the pivoted moveable arm to move toward the VCB. It may be noted that the mechanism does not work if the front door is in open condition/unlatched and when the door is latched but the VCB is not inserted inside the VCB compartment.
[020] In a further embodiment of the present invention, an auto resetting arrangement is provided. The auto resetting arrangement has a pair of lateral springs 140 connected to the resetting pin on one side and to a pivot pin 142 passing through the moveable arm on another side. Resetting linkages are coupled to moveable arm such that if the mechanism is actuated by mistake and the movable lever comes out from the latch, it will get reset by just pushing it towards the door.
[001] In an embodiment, a slot 112 is provided on the fixed member and a pair of inwardly protruding members 114 are mounted along the slot thereby defining a guiderail. The guiderail is configured to receive a moveable plate 116. In this regard, the moveable plate moves on the guiderail along its length between a service position 330 and test position 340. In an embodiment, the moveable plate is coupled to the moveable arm whereby pivotal movement of the moveable arm forces the moveable plate to move along the length of the guiderail. In this regard, position of the moveable plate is indicative of the position of the vacuum circuit breaker. For instance, if the moveable plate is positioned at the service position, this indicates that the vacuum circuit breaker is in service position. Similarly, if the moveable plate is positioned at the test position, this indicates that the vacuum circuit breaker is in test position. As position of the moveable plate is visible on the front door, a user can easily identify the position of the vacuum circuit breaker by from the front of the vacuum circuit compartment. In an exemplary embodiment, the moveable plate is coupled to the moveable arm by using a connecting link rod 500.
[002] Figure 3 shows a front door of vacuum circuit breaker adapted with the mechanism as described hereinabove. In an embodiment, the fixed member is mounted on an inner surface of a front door 310 of a vacuum circuit breaker compartment 300. A horizontal slot 320 is also provided on the front door of the vacuum circuit breaker compartment. In an embodiment, the fixed member is mounted on the inner surface of the front door of the vacuum circuit breaker such that the slot on the fixed member is positioned adjacent to the horizontal slot of the front door thereby creating a recess through both the front door and the fixed member.
[003] In operation, during racking in of vacuum circuit breaker, the vacuum circuit breaker moves away from the front door inside the vacuum circuit breaker compartment. As the second end of the moveable arm is resting on the front surface of the vacuum circuit breaker, the moveable arm pivotally moves away from the fixed member. The moveable plate also moves inside the guiderails towards the service position thereby indicating service position of the vacuum circuit breaker. Similarly, during racking out of the vacuum circuit breaker, the vacuum circuit breaker moves towards the front door inside the vacuum circuit breaker compartment thereby moving the moveable arm pivotally towards the fixed member. The moveable plate also moves inside the guiderails towards the test position thereby indicating test position of the vacuum circuit breaker as a result of movement of the moveable arm.
[004] Advantageously, position of the vacuum circuit breaker inside the vacuum circuit breaker compartment can be easily identified without looking inside the compartment through the window as moveable plate indicates the position of the vacuum circuit breaker on the front door of the vacuum circuit breaker compartment. Further, the moveable plate indicates position of the vacuum circuit breaker changing gradually between test & service positions, which also help to identify intermediate position of vacuum circuit breaker. Accordingly, the mechanism of the present invention provides a clear indication about position of the vacuum circuit breaker from front of the panel, which help in avoiding unsafe conditions and accidents.
[005] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.